Holy cr4p you’re determined!!!
There’s something wrong somewhere if it’s this difficult to build it…
Would you consider posting a zip of the build on github or somewhere, so people can just download and run it?

Great work!! Thank you for taking the time to do this, we are all in your debt. Is there a way to do this without a Linux computer? All I have are windows computers. I am very interested in getting this working on my RP3 and 5" lcd.

These instructions are now obsolete due to a change in QT version for QGCS. I’m working on making new instructions. I tried joystick with the old version, it worked, but without buttons. I’ve read that buttons should work with QGSC and Ardupilot now